Cats and paracetamol

A sad incident that occurred just the other day. A pug was admitted for treatment, in which there was a tumor on the paw and a scheduled operation was prescribed. Before the day of the operation, there were several days and the dog was prescribed maintenance treatment, giving injections with him, among which was an anesthetic. But the owners thought that the veterinary pain medication was not strong enough and they supplemented it with pills from a home medicine cabinet. The dog began to bleed, and the swelling on the paw immediately receded into the background. The dog did not endure such home treatment.

Among the intoxications caused by self-medication, paracetamol poisoning is most often. Pet owners often believe that paracetamol, aspirin, ibuprofen and other human medicines are also suitable for animals, but at a children’s dosage. But this is not so.
Paracetamol (or acetaminophen) is an aromatic amine, which in its structure is close to aspirin, but does not belong to the category of anti-inflammatory drugs of non-steroidal origin: it has analgesic and antipyretic properties, but not anti-inflammatory. In most animal species, paracetamol binds in the liver with glucuronic acid, which ensures its excretion through the kidneys. In cats, glucuronic binding is limited.
Dogs tolerate therapeutic doses of paracetamol comparable to human ones, and they show signs of intoxication only when they receive an extremely high dose or accidentally swallow a large amount of the drug, or with liver failure. In contrast, in cats, signs of intoxication appear at lower doses after a few hours (up to a day). Oral use of a bag of paracetamol (250 mg), i.e. children’s dose, causes the manifestation of clinical symptoms of intoxication in a cat weighing 3 kg. In the Yorkshire Terrier, which weighs as much as a cat, similar intoxication occurs from a 2- or 3-fold dose of paracetamol.
The toxic oxidizing effect of paracetamol is directed to red blood cells. Red blood cells can experience two main types of exposure: the conversion of hemoglobin to methemoglobin, which leads to oxygen starvation in the tissues, and the destruction of hemoglobin, which leads to hemolytic anemia. Other painkillers, especially aspirin, can lead to acute renal failure in cats.
Onion, garlic, naphthalene (antimole balls), zinc (impurities), propylene glycol can cause similar destruction of red blood cells.
Signs of poisoning:

general weakness

increased respiratory rate

salivation, vomiting

low body temperature

chocolate / brown gum appearance

swelling of the muzzle and / or paws

stomach discomfort

yellowing of the eyes

Symptoms develop within a few hours after intoxication. It would seem that if the animal survives on the first day, then the danger has passed. In the case of paracetamol poisoning, survival in the first 24 hours does not guarantee success, because only then does toxic damage to the liver begin, which is often irreversible and, ultimately, will lead to death. Recovery can take many months before the liver returns to a state before poisoning.